PTLA: Portola Pharmaceuticals Announces Presentation of Preclinical Data on Andexanet Alfa (PRT44545), Factor Xa Inhibitor Antidote, at 2013 European Society of Cardiology Congress Business Wire August 29, 2013 8:03 AM
SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)-- Portola Pharmaceuticals, Inc. (NASDAQ: PTLA [FREE Stock Trend Analysis]) today announced that it will present preclinical data on its investigational Factor Xa inhibitor antidote andexanet alfa (PRT4445*) in a moderated poster session at the upcoming 2013 European Society of Cardiology (ESC) Congress, which is taking place in Amsterdam from August 31-September 4.
“These data from a preclinical animal model are noteworthy because they demonstrate that the reversal of Factor Xa anticoagulant activity by andexanet alfa has the potential to reduce blood loss in anticoagulated patients experiencing an active bleed, an important point of differentiation with this compound,” said John T. Curnutte, M.D., Ph. D., executive vice president of research and development for Portola. “We have already established in a Phase 2 clinical study that andexanet alfa can reverse the anticoagulant activity of the Factor Xa inhibitor Eliquis® (apixaban), and, as part of an accelerated development plan, we expect to initiate a pivotal study in 2014 to further assess the effects of andexanet alfa on bleeding.”
Details of the moderated poster presentation follow:
Abstract title: PRT064445 (Andexanet Alfa) Reverses Rivaroxaban Induced Anticoagulation in a Rabbit Liver Laceration “Treatment” Model
Session: Antithrombotic Agents
Presentation date/time: August 31, 2013, 16:22 p.m. CEST
Location: Moderated Posters -- Village 9
Moderator: Stanley Hollenbach, J.D., vice president, pharmacology, Portola Pharmaceuticals
Andexanet alfa (proposed INN) is a novel recombinant, modified Factor Xa molecule designed to reverse the anticoagulant activity in patients treated with a Factor Xa inhibitor who suffer an uncontrolled bleeding episode or need to undergo emergency surgery. Andexanet alfa is similar to native Factor Xa, but has been modified to restrict its biological activity to the reversal of the anticoagulant effects of Factor Xa inhibitors. Andexanet alfa acts as a Factor Xa decoy that binds and sequestors direct Factor Xa inhibitors in the blood. Once bound to andexanet alfa, the Factor Xa inhibitors are unable to bind to and inhibit native Factor Xa. The native Factor Xa is then available to participate in the coagulation process and restore hemostasis.
Results from a Phase 1 single ascending dose safety and tolerability study of andexanet alfa conducted by Portola in 32 healthy volunteers showed no apparent safety signals, including no thrombotic adverse events and no antibodies against andexanet alfa, endogenous Factor Xa or Factor X. Results from a Phase 2 proof-of-concept study of andexanet alfa were presented at the 2013 Congress of the International Society on Thrombosis and Haemostasis, demonstrating reversal of the anticoagulant activity of Bristol-Myers Squibb's and Pfizer's Factor Xa inhibitor Eliquis® (apixaban).